The background study that aimed to define clinical, radiographic and pathologic characteristics of early breast cancer and its precursors, to determine the diagnostic criteria and patterns of criteria for detection and diagnoses of early breast cancer and to determine high-risk groups of patients has been partially completed by using discriminant analysis procedures on data carefully collected and edited over the past 12 years at Emory University. This present phase will calibrate discriminant function classifications and provide estimates of probability of breast cancer in each risk hierarchy (patient risk). The scheme will then be applied to populations independent of those used to define the discriminant functions to evaluate its effectiveness and usefulness. The data base will be up-dated and augmented in preparation of analysis for study of treatment planning, prognosis and natural history of breast cancer.